A piezoelectric resonator device is an electronic device in which are hermetically sealed driving electrodes of a piezoelectric resonator plate that cause piezoelectric resonance. Examples of the piezoelectric resonator device include a crystal oscillator, a crystal resonator and the like. This type of piezoelectric resonator device is constituted by a base made of a ceramic material and a lid made of a metal material. A housing of the piezoelectric resonator device is formed as a package having a rectangular parallelepiped shape. In an internal space of the package, the piezoelectric resonator plate is bonded to and held on the base with a conductive adhesive made of a fluid material. In the piezoelectric resonator device, the piezoelectric resonator plate in the internal space of the package is hermetically sealed by the base and the lid bonded to each other (see, for example, Patent Document 1).
The piezoelectric resonator device described in Patent Document 1 includes a thermistor element for use as a temperature sensor unit. In the piezoelectric resonator device, the base is constituted by: a bottom portion; a first wall portion extending upward from the bottom portion along the outer periphery of one main surface of the base; and a second wall portion extending downward from the bottom portion along the outer periphery of the other main surface of the base. Thus, the base is formed so as to have an H-shape in cross-section. The base includes a first cavity surrounded by the bottom portion and the first wall portion. The piezoelectric resonator plate is disposed in the first cavity. The base also includes a second cavity surrounded by the bottom portion and the second wall portion. The thermistor element is disposed in the second cavity.